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United States Patent | 5,315,288 |
Coward | May 24, 1994 |
Two volume levels may be produced in a backup alarm merely by reversing polarity of the DC power connections to the circuit of the present invention. The magnitude of output power produced by any device powered by a DC source may be switched between two levels merely by reversing polarity of the power source connected to the device when used with a circuit of the present invention.
Inventors: | Coward; Mark T. (Boise, ID) |
Assignee: | Electronic Controls Company (Boise, ID) |
Appl. No.: | 705035 |
Filed: | May 24, 1991 |
Current U.S. Class: | 340/463; 340/384.7; 340/474; 340/692; 381/57; 381/102; 381/104 |
Intern'l Class: | B60Q 001/26 |
Field of Search: | 340/474,692,384,463 381/57,102,104 |
3943507 | Mar., 1976 | Neal et al. | 340/463. |
4603317 | Jul., 1986 | Gailbreath et al. | 340/463. |
4785285 | Nov., 1988 | Teich et al. | 340/505. |
4881058 | Nov., 1989 | Berry, III | 340/384. |
4929924 | May., 1990 | Buyak et al. | 340/384. |
Wireless World (Jan. 1980) vol. 86 No. 1529. |